The myth of 420,000 cats in 7 years

I've seen this thing about 420,000 cats in 7 years being stated as fact on TCS now and then. I know I'm also not the first person on TCS to point out the problems with this, but I figure it can't hurt to say it again so I decided to write something about it. I wasn't sure where to put it , so it's ending up here:

I just wish well-meaning, cat-loving, cat-helping people would stop repeating the debunked claim about a pair of cats left unaltered producing 420,000 cats in 7 years. , an urban legend / propaganda "statistic" that has taken on a life of its own and can backfire against cat welfare.

If cats were reproducing at that rate, many countries would have TRILLIONS of homeless cats.

There have been articles debunking it and major animal organizations now say they don't think it is accurate. Even HSUS ( who used to have it on their website and who were often credited as being the source) say they no longer believe it and they don't even know where the number originally came from.

It's true that it is often preceded by , " theoretically" . I guess people figure that makes it "true" , if in theory one could do the math that way. But that makes it just an exercise in arithmetic, divorced from reality. A more realistic estimate in the low hundreds has been proposed based on studies of feral colonies. but that doesn't have the attractive shock value of 420,000.

I understand that some people / groups say this with good intentions because they hope it will get people to spay / neuter their cats.

But I don't like repeating this myth because:

This very same faux statistic is used as an argument by opponents of TNR that it can't be effective since if you just miss trapping a smart queen and tom in a managed colony they'll soon have produced hundreds of thousands more cats. (The same argument would apply to trap & kill, but they sometimes think a really intensive trap and kill effort would work, or suggest other forms of mass slaughter.) If someone already dislikes free-roaming cats and hears that just a pair of them could end up creating 420,000 in 7 years, that's not likely to make them feel friendlier to the cats, and some cat haters may find in such numbers the justification for getting rid of cats by any means.

As an argument for / attempt to shock people into spay/ neuter of pet cats, this figure sounds so exaggerated that it can lead people to doubt everything said by the group or individual making such a claim. More accurate numbers might actually be more effective since they're more believable . Even if the number is 100 or 200, that's still a good reason to s/n/.

It makes things sound so utterly hopeless . It could lead to a defeatist attitude that it is impossible to even get to a very low kill rate in shelters... so why bother trying to make any changes in the way things have always been done?

Some feral cat advocates have been trying for a while to track down where this stat came from.

The Feral Cat Spay Neuter Project in Seattle, WA, USA, challenged the 420,000 figure and tried to come up with a more realistic estimate. Using population data from studies of feral colonies, mathematicians arrived at a more realistic estimate of 100- 400 cats -- but that's if no adult cats die. The Feral Cat Times Feb 2006 The info is on page 2 " Dispel the Myth: 420,000 Cats?!" and on page 3. " How Many Kittens in Seven Years?"

"Tall tales about rampant feline reproduction and predation rates, and their persistence even after being debunked or challenged, can be a matter of life and death for feral and free-roaming cats. If large numbers of people believe -- and convince public policy makers to believe -- that a single unspayed cat can produce 420,000 descendents in seven years, and that cats kill a billion songbirds every year, it becomes very easy to argue for the mass trapping and slaughter of free-roaming cats in the name of protecting birds."

Click to expand...

Franny Syufy of cats.about.com admits she was one of the many advocates who repeated this number as an argument for spay/ neuter, but didn't know where it came from and hadn't thought about how it could actually be harmful 420,000 Cats in 7 Years : True or False?

There are now many sources saying it's a myth , giving links or quoting the earlier articles, but unfortunately it's one of those things that is hard to get rid of. I just wish we here at TCS could stop contributing to it.

But I guess I am part of the problem because I should have said something before ; not just when it's someone using this along with other false claims about feral cat population and predation, but when it is someone using it for what was probably the original intent -- promoting spay/ neuter. Yet it is certainly possible to point out that this is incorrect ,but frame that in a way that is still an argument for getting your cats altered.

I had not really thought about it other than it sounded very unrealistic. I grew up on a farm so there were a lot of ferals or strays that had gone feral and that was a time when there was no TNR done. If that number were realistic there would've been huge numbers of cats running around. I had also not thought about the negative impact caused by that number being repeated so often that people have accepted it as true. I think that difference in thinking is the difference between being a cat lover and not being a cat lover. Cat lovers would be more determined to try to get all cats spayed/neutered. People who aren't cat lovers would think in terms of more drastic solutions.

You start out with one cat having kittens as often as she comes into heat, plus one tom to fertilize her. After a year, you have X cats, which you divide into pairs and apply the same calculation to.

Seven years is as long as you could reasonably expect the first cat to survive feral.

So, yeah, after seven years, if every cat survives and reproduces, you do have that many cats.

The reason this doesn't play out in reality is that most of those kittens don't survive. Say Generation 0 has twelve kittens the first year. If she's feral, none of the kittens might survive. Then the cats breeding during Generation 1 would still be just the first pair.

Or say Generation 0 is an indoor-outdoor housecat. Say she has her two or three litters that first year. Most of those kittens end up at shelters before they reproduce themselves, or they get dumped on the street, where they die. Instead of having twelve cats in it, Generation 1 might have only four cats.

The idea of thousands of cats is theoretical and meant to be purely theoretical, but it still works as an argument about why cats need to be neutered. If you don't get your cat neutered, then in order to stop those thousands of cats (long before they become thousands, because even five cats are a handful), some of those kittens must die.

Everyone knows that we aren't surrounded by cats to the extent that the math tells us we would be if they all survived. The logical conclusion: Some of those cats die. In order to prevent needless deaths, neutering is the only humane option.

Thank you for posting some commonsense truth!!! I only wish that your article was in the Lounge Forum where more people could become educated. I have been troubled by that myth for years. I do my best to explain otherwise but most people do not believe me since my opinion is so unusual. However, I CAN tell them that last year, I got 10 kittens from my largest colony of ferals and of those 10, only 1 lives today - the others were ill and eventually had to be euthanized; my only comfort is that I brought them home to my yard and they had a good life of good food, a great safe yard to play in and good medical treatment. Feral kittens born to unvaccinated moms typically don't last long